6. INTRODUCTION
➢ JOSEPH ASPDIN: INVENTED PORTLAND CEMENT IN U.K. IN 1824.
➢ HE USED A MIXTURE OF LIMESTONE, CLAY & WATER.
➢THIS MIXTURE WAS HEATED AT HIGH TEMPERATURES.
➢ON 21ST OCT, 1824 WAS GRANTED A PATENT.
+ + WATER = CEMENT
10. MANUFACTURING OF CEMENT
RAW MATERIAL
EXTRACTION & STORAGE
CORRECTION OF
PROPORTIONS
PULVERIZE CLINKER & ADD
GYPSUM
PULVERIZATION
(POWDERY FORM) IN BALL
MILL
CALCINATION IN KILN
[HEATING]
FORMATION OF CLINKER &
ITS COOLING
STORAGE & PACKING
11. MANUFACTURING OF CEMENT
➢CALCINATION:- HEATING OF SUBSTANCE UPTO HIGH TEMPERATURES BUT BELOW MELTING POINT.
➢IT ENABLES THE SUBSTANCE TO FUSE (FUSION).
➢IN THIS PROCESS GASES (CO2) IS EVOLVED.
➢TEMPERATURE IS KEPT AROUND 1300-1500O C IN ROTARY KILN.
BALL OR
TUBE MILLS
15. CONSTITUENTS OF CEMENT & THEIR ROLE
1. Lime Control strength & soundness. If lime
decreases, strength & setting time
decreases.
60-65 (63%)
2. Silica Gives strength. If increase, it increases slow
setting.
17-25 (20%)
3. Alumina Responsible for quick setting, if in excess it
lowers the strength.
3-8 (6%)
4. Iron Oxide (Fe2O3) Gives colour & helps in fusion of different
ingredients.
0.5-6 (3%)
5. Magnesia Imparts colour & hardness. If in excess,
causes cracks in mortar & concrete & leads
to unsoundness.
0.5-4 (2%)
6. Soda+Potash Residues, causes efflorescence and cracking. 0.5-1 (1%)
7. Sulphur Trioxide Makes cement unsound. 1-2 (1.5%)
CONSTITUENTS FUNCTIONS AVERAGE COMPOSITION
16. CONSTITUENTS OF CEMENT & THEIR ROLE
➢FLY ASH (1%) IS ALSO USED AS AN ADMIXTURE THESE DAYS TO
IMPROVE WORKABILITY, BUT DOES NOT AFFECT THE STRENGTH.
➢GYPSUM (2-3%) IS ALSO ADDED IN ORDER TO INCREASE SETTING
TIME.
17. CLINKER COMPOSITION
➢ 1. Tricalcium silicate ➢ Alite
➢ 2. Dicalcium silicate ➢ Belite
➢ 3. Tricalcium aluminate ➢ Celite
➢ 4. Tetra calcium alumino
ferrite
➢ Felite
Principal mineral compounds Formula Name Symbol
➢ Besides these major compounds, alkalies (Soda & Potash) are also present.
For high strength development proper cooling.: Ambient Temperature.
When Raw Materials fuses in kiln, the resultant compounds produced are Bogue compound.
18. CLINKER COMPOSITION
➢ It provides best cementing property and its formed when cement is well burnt.
➢ It provides early strength and is responsible for 7 days strength.
➢ It enables clinker easy to grind & increase resistance to freezing and thawing.
➢ Generates high heat of hydration (H.O.H) and increase solubility of cement in water.
➢ H.O.H=500J/gm
➢ It hydrates and hardens slowly and takes long time to add to strength that is later
strength.(ultimate strength)
➢ It enables clinker hard to grind & decrease resistance to freezing and thawing.
➢ Generates low H.O.H and decrease solubility of cement in water.
➢ It imparts chemical resistance.
➢ H.O.H= 260J/gm
1. Tricalcium silicate, C3S --- 25-50% (average= 40%)
2. Dicalcium silicate, C2S --- 25-40% (average= 32%)
19. CLINKER COMPOSITION
➢ It reacts immediately with water and is responsible for flash set (initial set).
➢ It is the first compound to react with water.
➢ It decreases setting time, hence increased shrinkage & cracking.
➢ It weakens resistance to sulphate attack.
➢ Volume change increase & hence cracking.
➢ H.O.H increase & lowers ultimate strength.
➢ H.O.H= 865J/gm.
➢ Responsible for flash set but generates less heat.
➢ Poorest cementing value.
➢ If increases, it decreases strength.
➢ H.O.H=420J/gm.
3. Tricalcium Aluminate, C3A --- 5-11% (average= 10.5%)
4. Tetracalcium Alumino Ferrite, C4AF --- 8-14% (average= 9%)
20. HYDRATION OF CEMENT
➢ Chemical Reaction of cement with water to produces C-S-H gel(Ettringite gel).
➢ These reaction are highly exothermic.
➢ Only C3S & C2S reacts with water to produce C3S2H3(Calcium silicate hydrate) which is mainly
responsible for strength & densifies as cement sets.
➢ Along with CSH gel Ca(OH)2 is also formed as by product.
➢ Ca(OH)2 is undesirable product because it causes sulphate attack.
➢ C2S gives better cementing product than C3S as it produces more gel & less Ca(OH)2 in long term.
➢ Hydration of cement depends on:-
I. Ingredients
II. Fineness increase => Surface area increase => Rate of reaction increase
III. Temperature increase => Rate of reaction increase.
21. HYDRATION OF CEMENT
➢ ORDER OF HEAT OF HYDRATION ---
C3A>C3S>C4AF>C2S
(865) (500) (420) (260)
➢ ORDER OF RATE OF HYDRATION ---
C4AF>C3A>C3S>C2S
➢ ORDER OF STRENGTH ---
C3S>C2S>>C3A>C4AF
➢ ORDER OF SETTING TIME ---
C3A>C4AF>C3S>C2S
Amount of heat produced by 1gm compound.
Speed of reaction- Mass of compound reaction per second.
22. SULPHATE ATTACK
➢ Solid sulphates does not affect severely.
➢ Water sulphates proves fatal as it reacts with gel & the volume of
cement paste(gel) increases in concrete or mortar.
C-A-H
(Calcium Alumino
Hydrate)
Calcium
Sulphoaluminates
(Higher volume)
C3A
Hydration
Sulphates
(Mg, Ca)
➢ These end products causes increase in volume by 227% which
causes the concrete to :-
1. Expansion
2. Extensive Cracking
3. Loss of bond between cement paste & aggregate.
➢ Gypsum(Calcium Sulphate) has to be controlled upto 3%. (Why?)
SOURCES OF SULPHATES:-
❖ IT OCCURS IN SOIL
❖ GROUND WATER.
❖ SEA WATER.
❖ PRESENT IN BRICKS.
❖ BACTERIAL ACTION IN SEWERS.
23. TESTS ON CEMENT
FIELD TEST
❑ COLOUR
❑ PRESENCE OF LUMPS
❑ STRENGTH
❑ DENSITY
CHEMICAL TEST
❑ LOSS ON IGNITION
❑ CHEMICAL COMPOSITION
LAB TESTING
PHYSICAL TEST
❑ FINENESS TEST
❑ CONSISTENCY TEST
❑ SETTING TIME TEST
❑ SOUNDNESS TEST
❑ STRENGTH
❑ H.O.H.
❑ SPECIFIC GRAVITY
➢ Tests are conducted to determine properties of cement & regulate various stages in manufacturing for quality.
24. FIELD TESTING
➢ Cement colour => Greenish grey
➢ If rubbed between fingers it should feel smooth not rough.
➢ If hand is inserted in bag on cement it should feel cool and not
warm.
➢ If thrown in a bucket of water it should sink and not float on
water
➢ A thin paste of cement should feel sticky between fingers
➢ It should be free from lumps (if present indicates absorption of
moisture from atmosphere)
➢ Briquettes(75x25x12 mm) made with 1:6 (cement:sand)
proportion shouldn’t break easily kept under water for 3 days.
25. PHYSICAL TESTS
1. FINENESS TEST
AIR PERMEABILITY APPARATUS
SIEVE TEST WAGNER TURBIDIMETER
CEMENT % RESIDUE BY
WEIGHT
OPC 10
RHC 5
CEMENT SPECIFIC SURFACE
AREA(m2 /kg)
OPC 225 (2250 cm2/gm)
RHC 325 (3250 cm2/gm)
• NURSE & BLAINE’S APPARATUS
• HEAD LOSS ∝ S.S.A.
• A Tank filled
kerosene & cement
particles are
allowed to fall.
• Turbidity is
measured which
gives idea about
SSA.
26. PHYSICAL TESTS
2. CONSISTENCY TEST
➢This test is use to find quantity of mixing water.
➢Normal consistency(P) is that percentage of water
required, viscosity will be such that vicat’s plunger
penetrates upto a point 5-7 mm from bottom of the
mould.
➢It is useful in performing other tests.
27. PHYSICAL TESTS
INITIAL SETTING TIME FINAL SETTING TIME
3. SETTING TIME TEST
➢Square needle 1x1 mm is
released and it penetrates only
5-7 mm from bottom of the
mould.
➢O.P.C. not less than 30 min.
➢L.H.C= 1 hr
➢Lime Pozzolana cement= 2 hr
➢ The time at which needle
makes an impression but the
annular collar fails to do so.
➢ F.S.T. not more than 10 hr.
Sample = 300 gm + 0.85P
28. PHYSICAL TESTS
Attachment Test
10 mm diameter plunger Consistency test
1 mm2 square needle Initial setting time
5 mm dia. annular collar Final setting time
29. PHYSICAL TESTS
4. SOUNDNESS TEST
(Change in volume of cement after setting)
LE-CHATELIER’S APPARATUS AUTOCLAVE TEST
➢ It measures unsoundness due to free lime only.
➢ Unsoundness of cement should be limited to 10 mm.
➢ It measures unsoundness due to
both free lime & magnesia only.
➢ Expansion of cement should not
be more than 0.8%.
Sample=100gm cement + 0.78P
30. PHYSICAL TESTS
5. STRENGTH TEST
COMPRESSIVE STRENGTH TENSILE STRENGTH
➢ Sample= Cement + sand (1:3) +(P/4 +3)%water.
➢ 3 cubes of size 70.6 mm are prepared & gradual
compressive load is applied.
➢ Average strength of 3 cubes is compressive
strength.
➢ Sample= Cement+sand(1:3) +(P/5 +2.5)% water.
➢ 6 briquettes are prepared & gradual load is
applied.
➢ Average strength of 6 briquettes is tensile
strength.
31. PHYSICAL TESTS
6. H.O.H. is measured by
CALORIMETER.
7. SPECIFIC GRAVITY is measured
by
LE-CHATELIER’S FLASK.
➢ For OPC, G=3.15
32. CHEMICAL TESTS
LOSS ON IGNITION
➢1 gm sample is heated in muffle furnace & loss in
weight is observed, which should not be more than 4%
in general.
CHEMICAL COMPOSITION
➢ Ratio of Alumina/iron oxide should not be more than
0.66.
➢ Weight of magnesia should not be more than 6%.
➢ Lime Saturation factor should be between 0.66 to 1.02.
33. TYPES OF CEMENT
1. ORDINARY PORTLAND CEMENT
2. RAPID HARDENING CEMENT (RHC)
➢The common 3 grades are:- OPC 33, OPC 43, OPC 53.
➢3 day strength= 50%(1/2) of 28 day strength.
➢7 day strength= 67%(2/3) of 28 day strength.
➢Fineness= 2250 cm2/gm.
➢I.S.T. >=30 min & F.S.T. <=10hr(600 min)
➢C3S is increased, C2S is decreased + finer grinding.
➢Fineness= 3250 cm2/gm.
➢I.S.T. =30 min & F.S.T. =10hr(600 min)
➢Uses- Road repairs, in cold countries, for fast removal of shutter.
➢1 day strength=16 N/mm2
34. TYPES OF CEMENT
3. EXTRA RAPID HARDENING CEMENT (ERHC)
4. HIGH ALUMINA CEMENT
➢R.H.C. + 2% CaCl2
➢Uses- Road repairs, in cold countries, for fast removal of shutter.
➢Mixing + Transporting + Placing of concrete should be within 10 min.
➢Accelerator = Calcium Chloride.
➢Bauxite + limestone + iron oxide + increase fineness + high temperature.
➢It is similar to RHC but C3A is absent.
➢Uses- Road repairs, in cold countries, for fast removal of shutter, refractory
cement (heat resistant), high chemical resistance.
35. TYPES OF CEMENT
5. SULPHATE RESISTING CEMENT
6. PORTLAND SLAG CEMENT
➢It is similar to OPC but C3A is decreased + finer grinding.
➢Uses- Lining of sewers, canals, in coastal areas, in sea waters.
➢Portland cement clinker + granulated blast furnace slag + gypsum.
➢High chemical resistance(sulphate resistance), low H.O.H.
➢Uses:- Marine works.
36. TYPES OF CEMENT
7. LOW HEAT CEMENT (LHC)
8. PORTLAND POZZOLANA CEMENT
➢Low contents of C3A & C3S & more contents of C2S.
➢I.S.T. = 1 hr (60 min) & F.S.T. =10hr(600 min)
➢Slow rate of hardening, slow strength development,
prevent shrinkage & cracking decrease.
➢Uses:- Mass concreting works, high temperature places.
➢ Portland cement + pozzolanic materials + finer grinding.
➢ Pozzolana(siliceous material) + Ca(OH)2 =Pozzolana-lime compound (cementitious)
➢ Low rate of strength development, decrease in early strength, low HOH.
➢ Uses:- Mass concreting works, marine works.
37. TYPES OF CEMENT
9. WATER REPELLANT CEMENT (HYDROPHOBIC CEMENT)
➢OPC Clinker + 0.1% oleic acid or stearic acid.
➢Uses:- In basements, water tight structure.
10. WHITE & COLOURED CEMENT
➢From pure white chalk + clay (free from iron oxide)= white cement.
➢Coloured cement = White cement+ 5-10% coloured pigment.
11. QUICK SETTING CEMENT
➢This cement is finer than OPC & Gypsum is not used.
➢I.S.T. =5 min & F.S.T. = 30 min.
➢Uses:- In running water or under water.
38. QUESTION PRACTICE
Q1. When combined with cement which of the following constituents of
pozzolana combine with free lime released during the hydration of
cement?
A. SiO2 B. Al2O3
C. Fe2O3 D. MgO
Q2. If p is the standard consistency of cement, the amount of water used
in conducting the initial setting time test on cement is
A. 0.65p B. 0.85 p
C. 0.6 p D. 0.78 p
Q3. The most commonly used retarder in cement is
A. Gypsum B. Calcium chloride
39. QUESTION PRACTICE
Q4. For complete hydration of cement the w/c ratio needed is
A. <0.25 B. >0.25 but < 0.35
C. > 0.35 but < 0.45 D. > 0.45
Q5. During mass concreting which cement is recommended to be used
A. Rapid Hardening Portland Cement B. Low Heat Cement
C. Quick setting cement D. Sulphate Resisting Cement
Q6. Which of the following cement contains maximum percentage of
dicalcium silicate?
A. OPC B. Low Heat Cement
C. Quick setting cement D. Sulphate Resisting Cement
40. QUESTION PRACTICE
Q7. Le Chatelier’s apparatus is used for determining the
A. Setting time B. Soundness of cement
C. Tensile strength D. Compressive strength
Q8. The compressive strength of OPC after 3 days should not be less than
A. 7MPa B. 11.5 MPa C. 16 Mpa D. 21MPa
Q9. The main ingredients of Ordinary Portland cement are
A. Lime & silica B. Lime & alumina
C. Silica & alumina D. lime & iron
41. QUESTION PRACTICE
Q10. The normal consistency of ordinary Portland cement is about
A. 10% B. 20% C. 30% D. 40%
Q11. The initial setting time for OPC as per IS specifications should not be less
than
A. 10 minutes B. 30 minutes
C. 60 minutes D. 600 minutes
Q12. The final setting time for OPC as per IS specifications should be
A. 10 minutes B. 30 minutes
C. 60 minutes D. 600 minutes
42. QUESTION PRACTICE
Q13. For testing compressive strength of cement, the size of cube is used
A. 50 mm B. 70.6 mm
C. 100 mm D. 150mm
Q14. The main constituent responsible for initial setting of cement
A. C2S B. C3S
C. C3A D. None
Q15. After storage, the strength of cement
A. Decrease B. Increase
C. Remains same D. May increase or decrease
43. QUESTION PRACTICE
Q16. For testing compressive & tensile strength of cement, the cement mortar is
made by mixing cement & sand in proportions of
A. 1:2 B. 1:3
C. 1:4 D.1:6
Q17. High early strength of cement is obtained as a result of .........(coarse / fine)
grinding & burning the cement at...... (lower / higher) temperatures.
Q18. Which has low percentage of iron oxide?
A. Quick Setting Cement B. Low Heat Cement
C. Ordinary Portland Cement D. White Cement
44. QUESTION PRACTICE
Q19. Which cement is gypsum free ?
A. White Cement B. Quick setting cement
C. Low Heat Cement D. Ordinary Portland Cement
Q20. Gypsum used in cement .............. (accelerates / retards) the setting time
by reacting with C3A which is responsible for flash set (Stiffening of cement
paste within a few minutes after mixing).
Q21. Before testing setting time of cement one should test for
A. Soundness B. Strength
C. Fineness D. Consistency
45. QUESTION PRACTICE
Q22. High Alumina cement is produced by fusing together a mixture of
A. Limestone & Bauxite B. Limestone & Bauxite & gypsum
C. Limestone & Gypsum & Clay D. Limestone, Bauxite, Gypsum, clay & chalk
Q23. The increase of strength of cement during a period of 14 to 28 days is primarily
due to
A. C2S B. C3S
C. C3A D. None
Q24. For marine works, the best suited cement is
A. Low heat Portland cement B. Rapid Hardening cement
C. Ordinary Portland cement D. Blast furnace slag cement
46. QUESTION PRACTICE
Q25. A quick setting cement has initial setting time of about
A. 50 minutes B. 40 minutes
C. 15 minutes D. 5 minutes
Q26. The specific gravity of commonly available OPC is
A. 4.5 B. 3.15
C. 2.05 D. 1.00
Q27. If p is the standard consistency of cement, the amount of water
used in conducting the Le Chatelier’s soundness test on cement is
A. 0.65p B. 0.85 p
C. 0.6 p D. 0.78 p
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48. CONCRETE
❑ INTRODUCTION
❑MANUFACTURING OF CONCRETE
❑WATER CEMENT RATIO
❑STRENGTH OF CONCRETE
❑WORKABILITY
❑ADMIXTURES
❑DURABILITY
❑DEFECTS
❑PROPERTIES OF CONCRETE
❑SPECIAL TYPE OF CONCRETE
❑MIX DESIGN
51. CLASSIFICATION
❖ On the basis of strength
➢Low strength concrete (<20 N/mm2 )
➢Medium strength concrete (20 N/mm2 - 40 N/mm2)
➢High strength concrete (>40 N/mm2)
❖ On the basis of Bulk Density
➢Extra light weight concrete (<500 kg/m3)
➢Light weight concrete (500 -1800 kg/m3)
➢Dense weight concrete (1800 - 2500 kg/m3)
➢Super heavy weight concrete (>2500 kg/m3)
52. MANUFACTURING OF CONCRETE
1. BATCHING
➢ Aggregates, cement & water are measured.
➢ There are two methods of batching:-
a. Weight batching
b. Volume batching
2. MIXING
➢ To obtain a homogenous & uniform mixture, we mix concrete in 2 ways:-
a. Hand mixing
b. Machine mixing
➢ IS 456 suggests approximately mixing time as 2 minutes.
➢ In general, 20 revolutions of concrete in mixer provides sufficient mixing.
54. MANUFACTURING OF CONCRETE
4. PLACING
➢Beams, Columns, Slabs, Highways, Runways…
➢Mass Concreting- Dams, Bridges etc.
➢Under water Concreting- Tremie pipe (Very
high slump value taken around 150-200 mm)..
55. MANUFACTURING OF CONCRETE
5. COMPACTION
➢The process of removal of air voids & to make it
dense.
➢ It is done in following ways:-
a. Hand rodding
b. By giving shocks & pressure
c. Mechanical vibration
1.Needle vibrator
2. Shutter(External) vibrator
3. Surface vibrator
4. Vibrating table
56. MANUFACTURING OF CONCRETE
6. FINISHING
➢ The process of levelling & smoothening the top surface of freshly
placed concrete.
➢ Screeding , floating & Trowelling is done.
Floating Trowelling
57. MANUFACTURING OF CONCRETE
7. CURING
➢ Cement gains strength & hardness because of water hence the pores
should remain saturated.
➢ To compensate loss of water & reduce shrinkage, cracking.
➢As per IS 456 minimum curing period is 7 days at 90% humidity.
➢Methods:-
1. Sprinkling water
2. Gunny bags
3. Ponding
4. Steam Curing
58. WATER CEMENT RATIO
➢According to Abram’s law:-
Strength of fully compacted
concrete is inversely proportional
to W/C ratio.
𝑊𝑎𝑡𝑒𝑟
𝐶𝑒𝑚𝑒𝑛𝑡
∝
1
𝑆𝑡𝑟𝑒𝑛𝑔𝑡ℎ
59. STRENGTH OF CONCRETE
1. COMPRESSIVE STRENGTH
➢ Characterstic compressive strength is that strength below which not
more than 5% of test results are expected to fall.
60. STRENGTH OF CONCRETE
Procedure for compressive strength testing:-
➢ Test specimens 150 X 150 X 150 mm is recommended as per IS.
➢ Mixed concrete is filled in mould in layers of 50 mm, each layer tamped 35
times(for 15 cm cube) with bar of 16 mm dia. & 600mm long.
➢Test specimens are stored at a temp. of 27 +/- 30C at
90% humidity for 24 hour from time of addition.
➢ After these remove from moulds & place in water for
28 days before testing.
➢Compression testing machine should be apply gradual
load of 14N/mm2 per minute until specimen is crushed.
➢ Average of 3 values is taken as compressive strength.
62. STRENGTH OF CONCRETE
2. FLEXURAL TENSILE STRENGTH
➢ It indicates modulus of rupture or tensile strength of concrete in
bending.
➢ As per IS code fcr= 0.7 𝒇𝒄𝒌
63. STRENGTH OF CONCRETE
3. SPLIT TENSILE STRENGTH
➢ This is a standard test to measure tensile strength in an indirect way.
64. STRENGTH OF CONCRETE
➢Order of strength:-
Direct tensile < Split tensile(fct) < Flexural tensile(fcr) < Compressive strength(fck)
➢ FACTORS affecting strength of concrete:-
• Size of specimen
• Moisture condition
• Air voids
• Rate of loading
• Age of cement
• Degree of compaction
• Type of aggregate
65. WORKABILITY
➢It is defined as amount of useful internal energy
required to produce full compaction.
𝑊𝑜𝑟𝑘𝑎𝑏𝑖𝑙𝑖𝑡𝑦 ∝
1
𝐶𝑜𝑚𝑝𝑎𝑐𝑡𝑖𝑜𝑛 𝑒𝑛𝑒𝑟𝑔𝑦
∝
1
𝑉𝑜𝑖𝑑𝑠
➢Factors affecting strength of concrete:-
➢ Water content
➢ Texture of aggregate
➢ Size of aggregate
➢ Shape of aggregate
➢Grading of aggregate
67. MEASUREMENTS OF WORKABILITY
2. COMPACTING FACTOR TEST
➢ It is lab test & used to measured workability
having low to medium slumps.
68. MEASUREMENTS OF WORKABILITY
3. VEE-BEE CONSISTOMETER TEST
➢ It is used to measure workability of very low to low slumps.
➢ The time required for the shape of concrete to change from
slump shape to cylindrical shape is known as VEE-BEE degree.
69. MEASUREMENTS OF WORKABILITY
4. FLOW TEST
➢It is lab test & used to measure workability having
high to very high slumps.
𝐹𝑙𝑜𝑤 % =
𝑆𝑝𝑟𝑒𝑎𝑑 𝑑𝑖𝑎𝑚𝑒𝑡𝑒𝑟 𝑐𝑚 − 25
25
𝑋 100
71. CHEMICAL ADMIXTURES
1. PLASTICIZERS
➢ It improves plasticity in fresh concrete.
➢ It improves workability for given W/C ratio.
➢ To achieve higher strength for given W/C ratio.
➢ It reduces water requirement by 10%.
➢ Examples:- Lignosulphonic acids, hydroxylated carboxylic
acids.
72. CHEMICAL ADMIXTURES
2. SUPERPLASTICIZERS
➢ They produce flowing concrete.
➢ Similar in action to Plasticizers.
➢ It reduces the water requirement by 20-40%.
➢ Examples:- Sulphonated melamine formaldehyde condensates,
modified lignosulphates etc.
3. RETARDERS
➢ These slow down the chemical reaction of cement & water.
➢ It increases setting time & slow down initial strength gain.
➢ Examples:- Sugar, lignins, phosphates, tartaric acid etc.
73. CHEMICAL ADMIXTURES
4. ACCELERATORS
➢ These speed up the chemical reaction of cement with water.
➢ Examples:- Calcium chloride, NaCl, Na2SO4, NaOH etc.
5. AIR ENTRAINERS
➢ It introduces air in form of tiny bubbles distributed uniformly.
➢ Examples:- Neutralized vinsol resin, wood resins etc.
➢ Uses:- Improves workability, reduces bleeding & segregation.
74. DURABILITY OF CONCRETE
➢ If concrete serves its purpose for entire design life, it is said
to be durable.
Factors affecting Durability:-
• Permeability
• Freezing & thawing
• Sulphate attack
• Acids & oils
• Sewage
• Frost action
75. DEFECTS IN CONCRETE
1. CRACKS
➢ It occurs due to unsound materials, freezing &
thermal effects, high w/c ratio etc.
➢ It reduces durability.
➢Acceptable limits of crack width is 0.1- 0.3 mm.
2. EFFLORESCENCE
➢Appearance of white fluffy patches on concrete
surface because salts leaches out & deposits on
surface.
76. DEFECTS IN CONCRETE
3. SEGREGATION
➢ When coarse aggregate, fine
aggregate & paste separates from each
other.
➢ Causes:- Dropping from heights,
excessive vibrations.
4. BLEEDING (LAITANCE)
➢ When mixing water flows out from
the surface from freshly placed
concrete is usually due to excessive
vibrations to achieve full compaction
77. PHYSICAL PROPERTIES OF CONCRETE
➢The stress strain curve is non linear.
➢Concrete is brittle.
➢Elastic modulus of concrete in
compression is
𝐸𝑐 = 5000 𝑓𝑐𝑘
➢ Poisson’s ratio varies in between 0.1 to
0.3 .
78. SPECIAL TYPES OF CONCRETE
1. Light weight or Foam Concrete
➢It is manufactured by using foaming or air
entraining agents with slurry of cement.
➢These foaming agents form a large number of
minute air bubbles dispersed in the concrete
mass and makes it light
➢Sand can be omitted to form air voids.
➢It possess low coefficient of thermal
expansion and greater fire resistance.
➢can be used for light weight roofs, false
ceilings, light weight partition walls etc.
79. SPECIAL TYPES OF CONCRETE
2. Aerated concrete
➢It is manufactured from calcareous and silicieous
materials like cement, lime, pulverized sand, fly
ash etc. by entrapping air cells.
➢These entrapped air cells make the material light,
impervious and a good insulator of heat.
3. Heavy Weight Concrete
➢It can be produced by using specially heavy
weight aggregates and by compacting well.
➢These concretes can be suitably used for gravity
dams, retaining wall construction, atomic power
plant vessels etc.
80. SPECIAL TYPES OF CONCRETE
4. Pre-packed concrete
➢It is obtained by injecting cement sand
mortar under pressure to fill voids of already
packed and fully compacted coarse aggregate.
➢This concrete is quite dense and has very
small shrinkage.
5. Fibre Reinforced Concrete
➢ Along with main ingredients, discrete fibres
are also added.
➢ FRC is tougher & more resistant to impact.
81. MIX DESIGN
➢ We have to find quantity of ingredients such as cement,
fine aggregates, coarse aggregates, W/C ratio in order to
produce 1m3 concrete.
84. QUESTIONS
Q1. The optimum number of revolutions over
which concrete is required to be mixed in a mixer
machine
A. 10
B. 20
C. 30
D. 40
Q2. The minimum curing period as per IS 456 is…….
A. 3 days
B. 7 days
C. 21 days
D. 28 days
85. QUESTIONS
Q3. Compaction of concrete helps in
A. Segregation of aggregates
B. Removal of excess water
C. Increase of density
D. Addition of required air voids.
Q4. Increase in moisture content in
concrete
A. Reduces the strength
B. Increases the strength
C. Does not change the strength
D. None of the above
86. QUESTIONS
Q5. The approximate ratio of strength of 15 x 30 cm concrete
cylinder to that of 15 x 15 cm cube of same concrete is
A. 1.25
B. 1.00
C. 0.80
D. 0.50
Q6. The approximate ratio between the strength of cement
concrete at 7 days & 28 days is……
A. 0.25
B. 0.3
C. 0.7
D. 1.5
87. QUESTIONS
Q7. The ratio of direct tensile strength to that of modulus
of rupture is.......
A. 0.2
B. 0.5
C. 0.8
D. 1.0
Q8. ..............is measured by applying load along diameter
of cylinder.
A. Flexural tensile strength
B. Compressive strength
C. Split tensile strength
D. Direct tensile strength
88. QUESTIONS
Q9. The tensile of concrete is approximately……….% of
compressive strength.
A. 10-20%
B. 30-40%
C. 50-60%
D. 70-80%
Q10. The splitting test for determining the tensile strength
of concrete gives more uniform results than any other
tension test.
A. True
B. False
C. May or not be true
89. QUESTIONS
Q11. The workability of concrete is increased by
A. Increasing the water content
B. Increasing the cement content
C. Using air entrainment admixture
D. All of these
Q12. As slump increases, the Vee-Bee time……
A. Increases
B. Decreases
C. Remains unchanged
D. None
90. QUESTIONS
Q13. As slump increases, the Compacting factor ……
A. Increases
B. Decreases
C. Remains unchanged
D. None
Q14. As slump increases, the spread in flow test ……
A. Increases
B. Decreases
C. Remains unchanged
D. None
91. QUESTIONS
Q15. Higher w/c ratio in concrete results in
...........(less/more) workable mix & ........(weak/strong)
mix.
A. less, weak
B. Less, strong
C. More, weak
D. More, strong
Q16. Hand compaction requires ........ (higher/lower)
workability than vibrations.
A. Higher
B. lower
92. QUESTIONS
Q 17. A rich mix has ........(high/low) aggregate-cement
ratio.
A. High
B. Low
Q18. The concrete should be cured at ........
A. 0oC
B. 20oC
C. 27oC
D. 40oC
93. QUESTIONS
Q19. Heavy reinforced section requires ..............
workability than light reinforced sections.
A. Higher
B. Lower
C. Any of the above
Q20. The factor which is most dominant in controlling
compressive strength of concrete?
A. W/C ratio
B. Min. Cement content
C. Fineness of cement
D. Aggregates content
94. QUESTIONS
Q21. Air entraining agent .......... (improves/degrades)
workability & durability & .......... (increase/decrease)
strength & density.
A. Improve, increase
B. Improve, decrease
C. Degrades, increase
D. Degrades, decrease
Q22.Water Cement Ratio to determine compressive
strength of cement is taken as
A. 0.2
B. 0.3
C. 0.4
D. 0.5
95. QUESTIONS
Q23. The property of ingredients to separate from
each other while placing the concrete……
A. Bleeding
B. Segregation
C. Bulking
D. Shrinkage
Q24. The size of cube to determine characteristic
compressive strength of concrete is
A. 150 x 150 x 150 mm
B. 175 x 175 x 175 mm
C. 200 x 200 x 200 mm
96. QUESTIONS
Q25. A slump cone is used primarily to provide
indication of which of following in concrete
A. Durability and finish
B. Air entrainment and chemical resistance
C. Strength and workability
D. Appearance and color
Q26. Main objective of compaction of concrete is
A. To eliminate air voids
B. to achieve maximum density
C. To provide proper contact between concrete
and reinforcing materials
D. All of the above.
97. QUESTIONS
Q27. Maximum value of minimum cement content
(kg/m3) of ordinary portland cement in design mix
of concrete (1m3)
A. 500
B. 450
C. 400
D. 360
Q28. The strength of concrete is directly
proportional to
A. Water Cement Ratio
B. Cement water ratio
C. Sand Cement Ratio
D. Water aggregate Ratio
98. QUESTIONS
Q29. Concrete in sea water shall be at least
............... grade in case of reinforced concrete.
A. M20
B. M25
C. M30
D. M40
Q30. Target strength for the mix proportioning (fck)
is given by :
A. fck - 1.65𝜎
B. fck - 2.65𝜎
C. fck + 1.65𝜎
D. fck + 1.65𝜎
99. QUESTIONS
Q31. The pH value of water used in concrete for
construction should not be less than
A. 5
B. 6
C. 7
D. 8
Q32.For most of the applications, water to
cement should be between:
A. 0.4 to 0.5
B. 0.5 to 0.55
C. 0.55 to 0.6
D. 0.6 to 0.65
100. QUESTIONS
Q33. The minimum cement content in moderately
exposed reinforced concrete with nominal weight
aggregates of 20mm nominal maximum size:
A. 220 kg/m3
B. 240 kg/m3
C. 280 kg/m3
D. 300 kg/m3
Q34.The height of the mould (cone) used for slump test
is :-
A. 150mm
B. 200mm
C. 300mm
D. 100mm
101. QUESTIONS
Q35. Aluminium powder in concrete is used as
A. Retarder
B. Air entraining agent
C. Accelerator
D. Super plasticizer
Q36. Tartaric acid can be used as
A. Retarder
B. Air entraining agent
C. Accelerator
D. Super plasticizer
102. QUESTIONS
Q37. When water content is very less it leads to
formation of air gaps in concrete known as .....
A. Voids
B. Honeycomb
C. Blister
D. Air bubbles
Q38. Addition of pozzolana ……………..workability.
A. Increase
B. Decrease
C. None
103. QUESTIONS
Q39. Which of the following is maximum?
A. Split tensile strength
B. Compressive strength
C. Bond strength
D. Flexural tensile strength
Q40. Lighter shallow sections requires…………
workability than heavier sections.
A. Higher
B. Lower
104. QUESTIONS
Q41. The slump of the concrete is increased by……
A. Plasticizers
B. Retarders
C. Accelerators
D. None
Q42. The addition of surfactants in the concrete mix
results in
A. Decrease in water cement ratio
B. Increase in strength of concrete
C. Both A & B.
D. None
105. QUESTIONS
Q43. The role of superplasticizer in a cement paste is to
A. Disperse the particles
B. Disperse the particles & remove air bubbles.
C. Retard setting.
D. All
Q44. Pozzolana added to concrete ........... the heat of hydration
hence used for mass concreting.
A. Increase
B. Decrease
C. Remains unchanged
D. None
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107. CONTENTS
❑ INTRODUCTION
❑ CLASSIFICATION OF BRICKS
❑ COMPOSITION OF GOOD BRICK EARTH
❑ PROPERTIES OF GOOD BRICKS
❑ MANUFACTURING OF BRICKS
❑ TESTING OF BRICKS
❑ DEFECTS OF BRICKS
❑ SPECIAL TYPES OF BRICK
108. INTRODUCTION
➢ Man has used brick for building purpose for
thousands of years. Bricks date back to 7000 BC.
➢ The artificial material of construction in form of clay
bricks of uniform size of shape are known as bricks.
➢ Standard size of modular brick :- 19 x 9 x 9 cm.
➢ Size of nominal size(with mortar) :- 20 x 10 x 10 cm.
➢ Weight of brick :- 3 to 3.5 kg.
109. CLASSIFICATION OF BRICKS
1. FIRST CLASS BRICKS
➢ It is table moulded & burned in kilns(well burnt).
➢ Deep red, cherry colour.
➢ It should have uniform appearance & texture.
➢ Smooth, rectangular, parallel & sharp edges.
➢ Should not break when dropped from a height of 1 to 2m.
➢ Metallic & clinging sound when struck with each other.
➢ Water absorption= 12-15% of its dry weight.
➢ Its absorption shall not exceed 20% when immersed in water
for 24 hours.
➢ Crushing strength >= 10 N/mm2.
➢Uses :- For construction of exterior walls, flooring etc.
110. CLASSIFICATION OF BRICKS
2. SECOND CLASS BRICKS
➢ It is ground moulded & burned in kilns(well burnt).
➢ Rectangular but slight irregularity is permitted.
➢ Surface may be slightly uneven.
➢ Metallic & clinging sound when struck with each other.
➢ Crushing strength >= 7 N/mm2.
➢ Water absorption= 16-20% of its dry weight.
➢ Its absorption shall not exceed 22% when immersed in
water for 24 hours.
➢ Uses:- Unimportant hidden masonry work & RCC work.
111. CLASSIFICATION OF BRICKS
3. THIRD CLASS BRICKS
➢ It is ground moulded & burned in clamps.
➢ It may be poorly burnt, overburnt or underburnt.
➢ Soft & reddish.
➢ Rough, irregular & distorted edges.
➢ Produce dull sound when struck with each other.
➢ Water absorption = 22 to 25% of its dry weight.
➢ Crushing strength >= 5 N/mm2 (3.5 to 7 N/mm2 )
4. FOURTH CLASS BRICKS ( JHAMA BRICKS )
➢ These are overburnt hence dark in color
➢ Badly distorted in shape & size.
➢ Brittle in nature.
112. COMPOSITION OF GOOD BRICK EARTH
❖ SILICA (50-60%)
❖ ALUMINA(20-30%)
❖ LIME(5-10%)
❖ OXIDE OF IRON(<7%)
❖ MAGNESIA(<1%)
❖ ALKALIES(<10%)
❖ CO2
❖ SO3
❖ H2O
S
A
L
I
M
113. COMPOSITION OF GOOD BRICK EARTH
1. SILICA
➢ Percentage - 50-60%
➢ Function – Absorbs water & provides durability.
➢ It prevents cracking, shrinkage, warping of raw brick.
➢ It reduces shrinkage during burning.
➢ Excess – destroys cohesion between particles & brick
becomes brittle.
114. COMPOSITION OF GOOD BRICK EARTH
2. ALUMINA
➢ Percentage – 20-30%
➢ Function – provides plasticity & helps in moulding.
➢ Excess – causes cracking & warping on drying & burning.
3. LIME
➢ Percentage – <10%
➢ Function – prevents shrinkage on drying, fusion.
➢ Excess – causes brick to melt & hence brick loses its
shape.
115. COMPOSITION OF GOOD BRICK EARTH
4. IRON OXIDE
➢ Percentage – <7%
➢ Function – improves impermeability & durability, red colour.
➢ Excess – causes cracking & warping on drying.
5. MAGNESIA
➢ Percentage – <1%
➢ Function – imparts yellow tint & reduce shrinkage.
➢ Excess – causes cracking & warping on drying.
116. PROPERTIES OF GOOD BRICK
➢ Size & Shape:- Smooth, rectangular, parallel, straight & sharp edges.
➢ Colour:- Uniform deep cherry red color
➢ Texture:- Rough so that mortar sticks properly.
➢ Hardness:- When scratched with finger nail it should not make any
impression.
➢ Soundness:- Metallic & clinging sound when struck with each other.
➢ Water absorption:- Not more than 20% of its dry weight when it is
immersed in cold water for 24 hours.
➢ Crushing strength:- >= 10 MPa
➢ Brick earth should be free from stones, grits etc.
118. MANUFACTURING OF BRICKS
1. PREPARATION OF CLAY(BRICK EARTH)
➢ UNSOILING – Removal of top layer of soil of about 200
mm depth.
➢ DIGGING – Clay is dug out & spread out
➢ CLEANING – Screening is done to make it free from
stones, pebbles, vegetable matter etc.
➢ WEATHERING – Clay is exposed to atmosphere for
softening.
➢ BLENDING – Clay is loosened & ingredients are spread
over it & dry vertical mixing is done.
➢ TEMPERING – Clay is added with sufficient quantity of
water & mixed under pressure to make it ready for
moulding.
122. MANUFACTURING OF BRICKS
3. DRYING
➢ Green Bricks contain high moisture content & if
burnt directly, it is likely to be cracked & distorted.
DRYING
ARTIFICIAL DRYING
NATURAL DRYING
HOT FLOOR DRIER TUNNEL DRIER
134. TESTING OF BRICKS
3. WATER ABSORPTION TEST
DRY BRICKS
CONSTANT MASS
(W1)
BRICK SATURATED
(W2)
OVEN 24 Hour cold water
Water Absorption = x100
➢ Water absorption should not be
greater than 20%.
W2 W1
W1
-
135. TESTING OF BRICKS
4. EFFLORESCENCE TEST
5. WARPAGE TEST
Concave Warpage
Convex Warpage
136. DEFECT OF BRICKS
➢ OVERBURNING – brick loses shape.
➢ UNDER BURNING – pores are not closed hence weak.
➢ BLOATING – Spongy swollen mass due to excess sulphur.
➢ BLACK CORE – Bituminuous matter or carbon present in brick
➢ EFFLORESCENCE – White patches due to alkalies leaching out.
137. DEFECT OF BRICKS
➢ CHUFFS – Deformation occurs if rain water falls on hot bricks.
➢ CHECKS – Lumps of lime causes volume changes by absorbing moisture.
➢ SPOTS – Due to sulphide, dark surface spots on surface.
➢ BLISTERS – due to trapping of air
➢ LAMINATIONS – Entrapped air in voids of clay forms thin lamina on
surface.
138. SPECIAL TYPE OF BRICKS
1. HEAVY DUTY BRICKS
➢ Efflorescence – Nil
➢ Water absorption < 10%
➢Uses:- Bridges, industrial foundation,
multi storey building.
2. BURNT CLAY PERFORATED BRICKS
➢Area of perforations should not be
more than 30 to 45% of face area.
➢Area of each perforation should not
be more than 500mm2
➢Use:- Partition walls, light structures
139. SPECIAL TYPE OF BRICKS
3. BURNT CLAY HOLLOW BRICKS
➢ Contains cavity blocks
➢ Reduce transmission of heat & sound.
4. REFRACTORY BRICKS/FIRE CLAY BRICKS
➢ It can resist a temp. of 1700oC.
➢ Water absorption = 4-10%.
➢ These bricks are burned for longer duration.
➢ Alumina, silica content is increased, lime is decreased.
➢ 3 types:- Acid bricks, Basic bricks & Neutral bricks.
140. MORTAR
➢ It consist of a binding material & fine aggregate.
CLASSIFICATION BASED ON BINDING MATERIAL
A. Cement mortar
B. Lime mortar
C. Gypsum mortar
D. Mud mortar
E. Asphalt mortar
F. Gauged mortar
TYPE OF WORK CEMENT SAND
Pointing 1 3
Reinforced
brickwork
1 3
Guniting 1 3
Masonry 1 4-5
Plastering 1 5-6
141. MORTAR
SPECIAL MORTARS
A. Fire resistant mortar
B. Light weight mortar
C. Packing mortar
D. Sound absorbing mortar
E. X-ray shielding mortar
GUNITING
➢ Application of mortar or concrete under
pressure through a cement gun.
➢ Compressive strength >40N/mm2
142. BRICK MASONRY
➢ BRICKS – Building units of masonry.
➢ MORTAR – Binding the building units & providing
strength to act as a single unit.
➢ BRICK MASONRY – Construction of building units
bonded together with mortar.
143. BRICK MASONRY
Terminology
1. Stretcher – Longer face (19 x 9) of brick
2. Header – Shorter face (9 x 9) of brick
3. Lap – Horizontal distance b/w vertical joint of
adjacent courses.
4. Perpend – Imaginary vertical line including
vertical joint of alternate courses.
5. Arris – Edge of bricks
6. Bed – Bottom surface of brick when laid flat
7. Quoin – Corner of masonry wall.
144. BRICK MASONRY
8. Closer – When bricks are cut along the length.
9. Bats – When bricks are cut along the width.
145. BRICK MASONRY
BOND – Lapping of bricks to enhance interlocking.
TYPES OF BONDS –
1. HEADER BOND
➢ 1 brick thick
➢ ¾ bat is used to overlap & maintain perpend
147. BRICK MASONRY
3. ENGLISH BOND
➢1 ½ brick thick wall.
➢ Queen closeris used to overlap & maintain perpend.
148. BRICK MASONRY
4. FLEMISH BOND
➢ 1 ½ brick thick wall.
➢ Queen closer is used to overlap & maintain perpend.
149. QUESTIONS
Q1. For more than 1 ½ brick thick & heavy loads
which bond is better?
A. English bond
B. Flemish bond
C. Stretcher bond
D. Header bond
Q2. Which bond is more pleasing in appearance?
A. English bond
B. Flemish bond
C. Stretcher bond
D. Header bond
150. QUESTIONS
Q3. Minimum strength of first class bricks should be…..
A. 3.5 N/mm2
B. 5 N/mm2
C. 7 N/mm2
D. 10 N/mm2
Q4. Which kiln produces more uniformly burnt bricks?
A. Updraught kilns
B. Downdraught kilns
151. QUESTIONS
Q5. In brick masonary, the mortar strength
should………...brick strength.
A. Exceed
B. Fall short of
C. Match
D. None
Q6. For 1m3 brick masonary, the number of modular
bricks needed is…..
A. 300-400
B. 400-450
C. 500-550
D. 600-700
152. QUESTIONS
Q7. Which class of bricks is used for superior masonry work ?
A. First class bricks
B. Second class bricks
C. Third class bricks
D. Fourth class bricks
Q8. First class bricks shall not absorb more than …….% of
water when immersed in water for 24 hour.
A. 15%
B. 20%
C. 22%
D. 25%
153. QUESTIONS
Q9. Which bricks are to be used for external masonry work
without plaster?
A. First class bricks
B. Second class bricks
C. Third class bricks
D. Fourth class bricks
Q10. Which bricks can be used for external masonry work
without plaster?
A. First class bricks
B. Second class bricks
C. Third class bricks
D. Fourth class bricks
154. QUESTIONS
Q11. Which class of bricks are generally used in foundation?
A. First class bricks
B. Second class bricks
C. Third class bricks
D. Fourth class bricks
Q12. Which class of bricks are generally used for construction
of temporary structures?
A. First class bricks
B. Second class bricks
C. Third class bricks
D. Fourth class bricks
155. QUESTIONS
Q13. Which constituent of brick earth provides plasticity?
A. Silica
B. Alumina
C. Iron oxide
D. Magnesia
Q14. Which component helps in fusion of compounds by lowering
fusion point?
A. Silica
B. Alumina
C. Lime
D. Magnesia
156. QUESTIONS
Q15. Which constituent of brick earth provides reddish colour?
A. Silica
B. Alumina
C. Iron oxide
D. Magnesia
Q16. Which constituent of brick earth increases melting point?
A. Silica
B. Alumina
C. Iron oxide
D. Magnesia
157. QUESTIONS
Q17. Which constituent of brick earth controls shrinkage most
effectively?
A. Silica
B. Alumina
C. Iron oxide
D. Magnesia
Q18. Excess of which constituent can melt the brick during burning?
A. Lime
B. Alumina
C. Iron oxide
D. Magnesia
158. QUESTIONS
Q19. Bricks are generally burnt in the temp. range of…
A. 500 – 800oC
B. 900 – 1200oC
C. 1200 – 1500oC
D. 1500 – 1800oC
Q20. Process of kneading clay with water under pressure
in pug mill?
A. Tempering
B. Kneading
C. Pugging
D. None
159. QUESTIONS
Q21. Which kiln produces more percentage of good quality bricks?
A. Bull trench kiln
B. Hoffman kiln
C. None
Q22. Which continuous kiln is more popular in India?
A. Bull trench kiln
B. Hoffman kiln
C. None
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161. TIMBER
❑ INTRODUCTION
❑ CLASSIFICATION OF TREE
❑ STRUCTURE OF TREE
❑ PROPERTIES OF TIMBER
❑ DEFECTS IN TIMBER
❑ PRESERVATION OF TIMBER
❑ FIRE RESISTANCE
❑ SEASONING OF TIMBER
❑ WOOD PRODUCTS
162. INTRODUCTION
Benefits of timber:-
➢ Efficient & fast installation.
➢ Environment friendly.
➢ Easy to craft with hand.
➢ High strength/weight ratio
Disadvantages:-
➢ Decay
➢ Variation in strength
➢ Moisture changes
164. CLASSIFICATION OF TREE
PROPERTY SOFT WOOD HARD WOOD
COLOUR Lighter Darker
GROWTH Faster Slower
WEIGHT Lighter Heavier
DENSITY Low High
CONVERSION Easy Difficult
RESINOUS MATERIAL Exist Do not exist
ANNUAL RINGS Distinct Indistinct
EXAMPLES Chir, fir, deodar etc. Teak, sal, shishum etc.
167. PROPERTIES OF TIMBER
1. DENSITY & SPECIFIC GRAVITY
➢ The average density(apparent specific gravity)
ranges from 450-950 kg/m3.
➢ The true specific gravity of wood is 1.5
2. MOISTURE CONTENT
➢ It is hygroscopic in nature.
➢ Recommended moisture content for structural
elements is 10-20%.
➢ Drying below fibre saturation point causes
shrinkage.
168. PROPERTIES OF TIMBER
3. SOUND CONDUCTIVITY
➢ Timber has high sound conductivity.
➢ Speed of sound ranges 3000-5000 m/s.
4. HEAT CONDUCTIVITY
➢ It is low.
➢ More along fibres than across fibres.
5. ELASTIC MODULUS
➢ It ranges between 5000-15000 kN/m3.
➢ Longitudinal direction > Transverse direction
169. PROPERTIES OF TIMBER
6. STRENGTH OF TIMBER
➢ TENSILE STRENGTH
Along the fibres > Across the fibres
➢ COMPRESSIVE STRENGTH
Along the fibres < Across the fibres
➢ SHEAR STRENGTH
Along the fibres < Across the fibres
ORDER OF STRENGTH
Tensile strength > Bending strength > Compressive strength
170. CHARACTERSTICS OF GOOD TIMBER
➢ High strength.
➢ Durable.
➢ High fire resistance.
➢ Sweet smell.
➢ Clear ringing sound.
➢ Straight fibres.
➢ Tough(High impact resistance)
➢ Hard medullary rays.
➢Regular annular rings.
➢Low water permeability.
171. DEFECTS IN TIMBER
➢DEFECTS DUE TO CONVERSION
➢DEFECTS DUE TO FUNGI
➢DEFECTS DUE TO INSECTS
➢DEFECTS DUE TO NATURAL FORCES
➢DEFECTS DUE TO SEASONING
178. DEFECTS IN TIMBER
• Callus- indicates soft tissue around wound.
• Twisted fibres- caused by twisting of young
trees by fast blowing wind.
Rind galls- indicates abnormal growth,
peculiar curved swellings. It develops
when branches are improperly cut off.
179. DEFECTS IN TIMBER
• Upsets- Ruptures occur when fibres are
injured by crushing or compression.
• Wind cracks- Shrinkage of external
surface leads to cracks.
Burls(excrescences)- formed when a tree receives
shock in its young age, irregular projections appear
on body.
182. PRESERVATION OF TIMBER
➢ It is done to increase the life of timber
➢ make durable
➢ To protect it from fungi, insects, etc.
➢ It doesn't increase strength & doesn’t remove moisture.
Types of preservatives:-
1. As Cu treatment
Composition:-
1 part of Arsenic pentoxide +
3 part of copper sulphate +
4 part of potassium dichromate.
This solution is used to protect from white ants.
183. PRESERVATION OF TIMBER
2. Chemical Salts
Salt solution is applied on timber surface.
3. Coal tar
Timber surface coated with coal tar.
- fire resistant
- unpleasant smell
- unsuitable for painting
184. PRESERVATION OF TIMBER
4. Creosote oil
➢It is tar oil type(distillation of tar)
➢It works as an antiseptic and poisonous for wood attacking
fungi.
➢Highly unpleasant smell.
5. Oil paints
➢2 to 3 coats of oil paints are applied.
➢Preserve from moisture and make it durable.
6. Solignum paints
➢Mixed with colour pigments and applied in hot state with brush.
➢Preserve from white ants and are highly toxic.
185. FIRE RESISTANCE
1. Special chemicals
➢ Ammonium sulphate soaking.
➢ Treated with antipyrine containing salts of
ammonia or boric or phosphoric acids.
2. Sir Abel's process
➢ Weak solution of sodium silicate (2 coats) +
slaked lime brush solution.
186. SEASONING OF TIMBER
➢Process of reducing moisture content of
freshly cut trees (moisture 50-60%) to make it
suitable for use.
Objective of seasoning:
▪ Reduce shrinkage & warping
▪ To increase strength, durability, workability of
dimensional stability.
▪ Make is suitable for painting
▪ Protection against fungi & insects
▪ Reduce its weight
187. METHODS OF SEASONING
NATURAL SEASONING ARTIFICIAL SEASONING
➢ BOILING
➢ CHEMICAL SEASONING
➢ ELECTRICAL SEASONING
➢ KILN SEASONING
➢ WATER SEASONING
METHODS
➢ AIR SEASONING
188. METHODS OF SEASONING
AIR SEASONING
➢ Rate of drying is slow.
➢ Cheap & simple.
➢ It reduces moisture content
of wood upto 12-15%.
➢ It makes timber durable,
tough & elastic.
189. METHODS OF SEASONING
BOILING
➢ It is a very quick method.
➢ Shrinkage is reduced, but strength
& elasticity is reduced.
CHEMICAL SEASONING
➢ Timber is immersed in salt solution.
➢ The time required is 30 to 40 days.
190. METHODS OF SEASONING
ELECTRICAL SEASONING
➢High frequency AC is passed across
timber.
➢The time required is 5 to 8 hours.
➢It is the most rapid method.
KILN SEASONING
➢Drying is carried in airtight chamber.
➢Strength & dimensional stability is
increased.
➢Less liable to attack of insects, fungi
191. METHODS OF SEASONING
WATER SEASONING
➢ Timber pieces partly immersed
in running water.
➢ Timber is taken out after a
period of about 2 to 4 weeks.
194. TIMBER & ITS USES
➢CHIR – Low quality work.
➢DEODAR – Light weight, Piles, Railway sleeper.
➢SAL – Ornamental work
➢TEAK – Strongest timber, high quality furniture, railway sleeper.
➢SHISHUM – Quality furniture(Heavy timber)
➢MULBERRY – sports goods.
➢BENTEAK – for boats.
➢KAIL - for making match boxes.
➢MANGO – cheap furniture, toys, cabinet works
195. QUESTIONS
Q1. Which component of trunk indicates dead portion?
A. Heart wood
B. Sap wood
C. Cambium layer
D. None
Q2. Which component of trunk indicates living portion?
A. Heart wood
B. Sap wood
C. Pith
D. Outer bark
196. QUESTIONS
Q3. Timber used for engineering & heavy construction are
derived from
A. Exogenous trees
B. Evergreen trees
C. Coniferous trees
D. Deciduous trees
Q4. The weight of the timber is measured at a moisture
content of……….
A. 5%
B. 12%
C. 20%
D. 50%
197. QUESTIONS
Q5. Fibre saturation point is a point at which there
is no free water in...............(cell cavities/cell walls)
& …............( cell cavities/cell walls) are fully
saturated.
A. cell cavities, cell cavities
B. cell cavities, cell walls
C. cell walls, cell walls
D. cell walls, cell cavities
Q6. Which is softer & lighter?
A. Sapwood
B. Heartwood
C. None
198. QUESTIONS
Q7. Which dries faster?
A. Sapwood
B. Heartwood
C. Both dries at same rate.
D. Ham Nahin Jante
Q8. A thin layer of sap which has not yet converted into
sap wood?
A. Inner bark
B. Outer bark
C. Sap wood
D. Cambium layer
199. QUESTIONS
Q9. Due to attack of dry rot, the timber:
A. Cracks
B. Shrinks
C. Reduces to powder
D. None
Q10. The timber having maximum resistance against white ants is
obtained from-
A. Chir
B. Sal
C. Shishum
D. Teak
200. QUESTIONS
Q 11. For manufacture of plywood, veneers are-
A. At right angles
B. Parallel
C. Inclined at 45o
D. Inclined at 75o
Q12. The most valuable timber may be obtained from
A. Chir
B. Sal
C. Teak
D. Maple
201. QUESTIONS
Q13. A well seasoned timber has a moisture content
.......
A. 10-12%
B. 25%
C. 50%
D. >50%
Q14. Kiln seasoning results in ...... density & better
dimensional stability.
A. Reduced
B. increased
202. QUESTIONS
Q15. Cambium layer is situated between inner bark &..........
A. Sap wood
B. Heart wood
C. Pith
D. None
Q16. Which method of sawing gives the strongest timber pieces?
A. Tangential method
B. Radial method
C. Ordinary sawing
D. Quarter sawing
203. QUESTIONS
Q17. Wood is soaked in ammonium sulphate to make it
A. Fungi resistant
B. Fire resistance
C. Insect resistance
D. None
Q18. Wood is impregnated in creosote oil in order to protect
against...
A. Fungi resistant
B. Fire resistance
C. Insect resistance
D. None
204. QUESTIONS
Q19. AsCu, comprises Arsenic pentoxide, copper
sulphate & potassium dichromate in the
proportion of
A. 1:2:3
B. 1:2:4
C. 1:3:4
D. 1:3:6
Q20. Which method of seasoning is good for
prevention of warping?
A. Kiln seasoning
B. Water seasoning
C. Chemical seasoning
205. QUESTIONS
Q21. The disease of dry rot in timber is caused by
A. Complete submergence in water.
B. Lack of ventilation
C. Alternate wet & dry conditions
D. None of these
Q22. The age of trees can be determined by:
A. Measuring diameter of pith
B. Thickness of bark
C. Length of medullary rays
D. Counting number of rings
206. QUESTIONS
Q23. The life of teakwood doors & windows is usually taken to be
A. 30 years
B. 40 years
C. 20 years
D. 60 years
Q24. Which timber is used to make goods used in sports industry?
A. Alder
B. Balsa
C. Mulberry
D. Asanfona
207. QUESTIONS
Q25. Radial splits in timber originating from bark and
narrowing towards the pith is known as
A. Cup shakes
B. Star shakes
C. Ring shakes
D. None
Q26. Cracks widest at centre which diminishes towards
outer circumference are
A. Cup shakes
B. Star shakes
C. Ring shakes
D. Heart shakes
208. QUESTIONS
Q27. Which method is adopted for rapid seasoning on large
scale to obtain any desired moisture content?
A. Kiln seasoning
B. Water seasoning
C. Chemical seasoning
D. Air seasoning
Q28. The defect in timber that causes longitudinal
separation between annual rings
A. Knots
B. Rind gall
C. Shakes
D. Twisted fibres
209. QUESTIONS
Q29. In the air drying process, the practical limit of moisture
content is
A. 0.05
B. 0.15
C. 0.25
D. 0.35
Q30. The hardwood is produced by which tree?
A. Chir
B. Kail
C. Fir
D. Shishum
210. FOLLOW ME ON:-
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INSTAGRAM ID - chetan_iitr
TELEGRAM CHANNEL - Chetan Sir(CE)
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212. INTRODUCTION
➢Stones are naturally occurring compact, solid & massive material that
make the crust of the earth.
➢ Stones are technically rocks which are in use since time immemorial.
214. IGNEOUS ROCKS
➢ Rocks formed by cooling & solidification of magma or lava.
➢ These rocks are strong & durable.
➢ They have crystalline & compact grains.
A. INTRUSIVE IGNEOUS ROCKS :- When cooling & crystallization of
magma occurs deep inside earth surface.
1. Plutonic rocks:- When magma cools deep inside earth.
Ex:- Granite etc.
2. Hypobassel rocks:- When magma cools at shallow depth.
Ex:- Gabbro, Diorite, Pegmatite etc.
B. EXTRUSIVE IGNEOUS ROCKS :- When cooling & crystallization of
lava occurs on top of earth surface.
Ex:- Basalt, trap, Andesite, Dacite, Rhyolite etc.
217. SEDIMENTARY ROCKS
➢ These rocks are formed by weathering of pre existing rock by external agencies such as wind, air,
water etc.
➢ These are formed by consolidation and cementation of sedimentary deposits.
A. MECHANICAL (CLASTIC) SEDIMENTARY ROCKS
➢ These sedimentary rocks are formed due to physical weathering by external agencies such as
running water, moving air, thermal effect, acids etc.
➢ Example: Conglomerate, Breccia, Sandstone, Silt stone, Mud stone, Shale, Gravel, Sand etc.
B. CHEMICAL SEDIMENTARY ROCKS
➢ These rocks are formed by chemical action of water, acids, alkalies etc on rocks
➢ Example: Clay, Limestone, Dolostone, Evaporites, Dolomite etc.
C. BIOLOGICAL(ORGANIC) SEDIMENTARY ROCKS
➢ These rocks are formed by remains of organisms such as sea animals.
➢ Example: Coal, Chert etc.
219. METAMORPHIC ROCKS
➢ These rocks are formed when pre existing rocks have been
changed in texture and composition by increased
temperature and pressure.
A. FOLIATED ROCKS
➢ This rocks have bands or strips on there surface or
throughout there body.
➢ Example: Slate, Schist, Gneiss etc
B. NON-FOLIATED ROCKS
➢ This rocks do not have bands or strips on their surface or
body.
➢ Example: Quartzite, Marble
220. METAMORPHIC ROCKS
STONE TYPE AFTER
METAMORPHISM
GRANITE IGNEOUS GNEISS
BASALT IGNEOUS LATERITE
LIMESTONE SEDIMENTARY MARBLE
MUDSTONE SEDIMENTARY SLATE
SANDSTONE SEDIMENTARY QUARTZITE
221. PHYSICAL CLASSIFICATION
A. STRATIFIED ROCK
➢Rock showing layered structure.
➢Example: Sandstone, Limestone, Shale
B. UNSTRATIFIED ROCK
➢Rocks not showing layered structure (cannot
be easily split in slices)
➢Example: Granite, Trap, Marble, Quartzite
etc.
222. CHEMICAL CLASSIFICATION
A. CALCAREOUS ROCKS:- Main component is Calcium carbonate.
Ex:- Marble, Limestone
B. SILICIOUS ROCKS:-Main component is Silica.
Ex:- Slate, Clay, Mudstone, Laterite
C. ARGILLACEOUS ROCKS:-Main component is Clay & Alumina.
Ex:- Sandstone, Trap, Quartz, Granite
223. QUIZ
STONE GEOLOGICAL PHYSICAL CHEMICAL
GRANITE Igneous Unstratified Siliceous
SANDSTONE Sedimentary Stratified Siliceous
LIMESTONE Sedimentary Stratified Calcareous
MARBLE Metamorphic Non foliated Calcareous
QUARTZITE Metamorphic Non foliated Siliceous
SLATE Metamorphic Foliated Argillaceous
225. MINERALS
➢ MONOMINERAL ROCK – Rocks having one mineral. Ex:- Gypsum
➢ POLYMINERAL ROCK – Rocks having more than one mineral. Ex:-
Granite, Basalt etc.
➢ Marble has Calcite mineral.
➢ Granite has quartzite & feldspar.
226. CHARACTERSTICS OF GOOD STONE
➢ Good in appearance
➢ Well seasoned stone
➢ Water absorption – not more than 5%.
➢ Easily workable, dressable
➢ Weathering resistance
➢ Fire resistance
➢ Hardness
➢ Toughness
➢ Crushing strength > 100 Mpa.
227. TESTING OF STONES
1. SMITH TEST
➢ To determine presence of soluble matter in stone.
2. CRUSHING TEST
➢ 3 Cubes of 40 mm are taken & average is reported.
228. TESTING OF STONES
3. ATTRITION TEST
➢ It is done in deval testing machine.
➢ 60 mm size stones are taken & rotated for 5 hours @ 30 rpm.
Rate of wear =
%𝒂𝒈𝒆 𝒐𝒇 𝒘𝒕.𝒑𝒂𝒔𝒔𝒊𝒏𝒈 𝟏.𝟓 𝒎𝒎 𝒔𝒊𝒆𝒗𝒆
𝑾𝒕.𝒐𝒇 𝒔𝒂𝒎𝒑𝒍𝒆
x100
Note:-
▪ Rate of wear <3% => Good quality
▪ Rate of wear =3% => Medium(tolerable)
▪ Rate of wear >3% => Bad & cannot be used in stone masonry.
229. TESTING OF STONES
4. HARDNESS TEST
➢ This test is done in dorry testing machine.
Coefficient of hardness = 20 -
𝑳𝒐𝒔𝒔 𝒊𝒏 𝒘𝒆𝒊𝒈𝒉𝒕
𝟑
Note:-
▪ Coefficient of hardness <14 => Poor hardness
▪ 14 < Coefficient of hardness <17 => Medium hardness
▪ Coefficient of hardness <17 => Very hard
230. TESTING OF STONES
5. IMPACT TEST
➢ This is done using anvil testing machine.
➢ In this 25 x 25 mm cylindrical aggregate is impacted by a hammer of
mass 2 kg & allowed to fall from different heights until specimen fails.
➢ Toughness coefficient= Height in cms from which specimen fails.
Note:-
▪ Coefficient of toughness <13 => Poor toughness
▪ 13 < Coefficient of hardness <19 => Moderate toughness
▪ Coefficient of hardness <19 => Very tough
231. TESTING OF STONES
6. ACID TEST
➢ It is used to determine weathering resistance capacity.
7. CRYSTALLINE TEST
➢ It is used to determine durability.
8. SPECIFIC GRAVITY
➢ It is in the range 2.5 to 3.
➢ For good stone, it is greater than 2.7
232. STONE MINING PROCESS
QUARRYING
➢ It is a multistage process by which rock is
extracted from ground & crushed to produce
aggregate.
SEASONING
➢ All freshly quarried stones contain a certain
amount of moisture known as quarry sap,
which makes them soft and easier to work
upon . Good stones should be free from
quarry sap.
234. USES OF STONE
➢ Abutment of piers – GRANITE
➢ Facing work – GRANITE, MARBLE
➢ Kankar – HYDRAULIC LIME
➢ Flooring – LIMESTONE, MARBLE, SANDSTONE
➢ Paving work – GNEISS
➢ Ballast & Foundation – BASALT, TRAP & GRANITE
➢ D.P.C. – SLATE
➢ Manufacture of putty - CHALK
235. FOLLOW ME ON:-
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• TELEGRAM CHANNEL - Chetan Sir(CE)
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• UNACADEMY LINK - https://unacademy.com/@chetansaxena
236. PAINTS AND VARNISHES
❑ PAINTS
❑ TYPES OF PAINTS
❑ CONSTITUENTS OF PAINTS
❑ PAINTING ON DIFFERENT SUTFACES
❑ DEFECTS IN PAINTS
❑ VARNISH
❑ TYPES OF VARNISH
❑ PUTTY
❑ DISTEMPER
237. PAINT
➢ A coloured substance which is spread over a surface
and dries to leave a thin decorative or protective
coating.
➢ Objectives:-
▪ Protection of base material
▪ Decorative purpose
▪ Increase durability.
▪ Simple maintenance
▪ Waterproofing
238. CHARACTERSTICS OF IDEAL PAINT
• Ease of application
• Reasonable drying period
• Forming a thin film without cracking
• Forming a hard and durable coating
• Its performance should not be affected by the weather
• Not harmful for users
• Attractive appearance
• Easily spread on surfaces
• Should remain free from cracks
239. TYPES OF PAINTS
1. OIL PAINT
➢ Oil paints are applied in three coats:- Primer,
undercoat and finish coat.
➢ Oil paints can achieve mat and glossy finishes, while
being durable and affordable.
➢ They are characterized by their ease of application,
and painted surfaces are easy to clean.
➢ Oil paints is commonly used in walls, doors, windows
and metal structures.
240. TYPES OF PAINTS
2. ALUMINIUM PAINT
➢ It is resistant to corrosion, electricity and
weather exposure.
➢ It is commonly used for metals and wood,
and some specific applications are gas
tanks, oil tanks, water pipes and radiators.
3. ANTI CORROSIVE PAINT
➢ It mainly resists corrosion hence
used on metal surfaces.
241. TYPES OF PAINTS
4. BITUMEN PAINT
➢ Bitumen paint is suited to many different
applications because of its weatherproofing,
corrosion resistance and adhesive properties.
➢ It is primarily used as a protective coating for
buildings, structures and items constructed from iron,
steel, concrete, masonry and wood.
5. CELLULOSE PAINT
➢ This type of paint is characterized by its quick
drying, smooth finish and hardness, while offering
resistance to water, smoke and acids.
242. TYPES OF PAINTS
6. ENAMEL PAINT
➢ This type of paint is produced by adding lead or zinc
to varnish.
➢ Enamel paints form hard and glossy coatings, which
are easily cleaned.
➢ They are characterized by being waterproof and
chemically resistant, offering good coverage and
color retention.
➢ Used in interior and exterior walls, windows, doors,
stairs etc.
243. TYPES OF PAINTS
7. PLASTIC PAINT
➢ This paint uses water as a thinner, and it is
available in a wide range of colors. It dries
very quickly and offers high coverage.
➢ It is used in slabs, decks, walls, ceiling of
auditorium and clubs etc.
8. CEMENT PAINT
➢ Cement paint is available in powder form, which
is mixed with water to achieve paint consistency.
➢ The base material is white or colored cement,
and it may also contain pigments, accelerators
and other additives.
➢ Cement paint is durable and waterproof, and it
is commonly used in rough internal and external
surfaces.